Transformer and coil winding method thereof

ABSTRACT

A transformer includes a core, a primary coil and a secondary coil. The secondary coil is formed by a first right-triangle area, ramp areas and a second right-triangle area. The first right-triangle area is formed by a set of layers providing a slanted surface and outwardly wound by continuous bending. A first layer of the set of layers is wound to be formed with an end wound position. A second layer subsequent to the first layer is wound to be started at a beginning wound position where is bent near the end wound position of the first layer. The rest layers of the set of layers are outwardly formed by repeating the winding sequence of the first and second layers. The ramp areas are wound along the slanted surface, and the second right-triangle area is inwardly wound opposite to the winding sequence of the first right-triangle area.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a transformer and a coil winding method thereof, and more particularly to a transformer and a coil winding method utilized to increase efficiency and reduce volume thereof.

2. Description of the Related Art

To use a conventional transformer in an environment with high voltage, ratio of winding of a primary winding and a secondary winding must be increased, i.e., the amount of the winding in the secondary winding must be increased. However, power jump occurs at the beginning and distal ends of the winding.

As shown in FIG. 1, a conventional transformer 1 is designed to overcome the above-mentioned power jump. The transformer 1 includes a core 10, a plurality of blocking walls 11 spaced at intervals on the core 10, a primary winding 12, and a secondary winding 13. One of the blocking walls 11 is utilized to separate the primary winding 12 from the secondary winding 13, and the secondary winding 13 is divided into several slots by the blocking walls 11. Because the amount of the windings in a single slot is few, power jump can be prevented.

However, at least 30 percent of the available space or volume for the windings is occupied by the location of the five blocking walls 11 formed on the core 10. Moreover, a higher voltage environment requires more blocking walls 11. Thus, the volume of the transformer 1 cannot be reduced, and utility and application of the structure thereof are relatively decreased.

BRIEF SUMMARY OF THE INVENTION

An object of the invention is to provide a transformer and a coil winding method for increasing efficiency and reducing volume thereof.

To achieve the above, the transformer of the invention includes a core includes a core including a first end and a second end; and a first coil wound around the core by forward winding the first coil from the first end of the core toward the second end of the core as a first layer, backward winding the first coil above the first layer toward the first end of the core from a position near a stop point of the first layer and repeatedly performing the forward and backward winding to form a first right-triangle area; winding the first coil along a slanted surface of the first right-triangle; and winding the first coil by a winding way opposite to that of the first right-triangle area.

The invention further provides a coil winding method for forming a coil on a core with a first end and a second end. A coil winding method for forming a coil on a core with a first end and a second end includes the steps of: forward winding the first coil from the first end of the core toward the second end of the core as a first layer, backward winding the first coil above the first layer toward the first end of the core from a position near a stop point of the first layer and repeatedly performing the forward and backward winding to form a first right-triangle area; winding the first coil along a slanted surface of the first right-triangle; and winding the first coil by a winding way opposite to that of the first right-triangle area.

According to the described features of the invention, the circle number of each of the circles is surrounded by circles with adjacent circle numbers. Therefore, the power jump can be prevented. Furthermore, the blocking walls noted in the conventional transformer can be omitted. Further, the first and second right-triangle areas of the transformer of the invention provide a higher efficiency than the conventional one, and, thus, costs and volume of the transformer can be reduced.

A detailed description is given in the following embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a cross sectional view of a conventional transformer;

FIG. 2 is a cross sectional view of a transformer of an embodiment of the invention; and

FIG. 3 is a schematic view showing steps of a winding method of the transformer of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.

FIG. 2 is a cross sectional view of a transformer 2 of an embodiment, and FIG. 3 is a schematic view showing steps of a winding method of the transformer 2 of FIG. 2.

Referring to FIG. 2, the transformer 2 of the embodiment includes a core 20 having a first end 201 and a second end 202, a first coil 21 wound around the core 20, a second coil 23 wound outside the first coil 21, a first insulating layer 22 disposed between the first and second coils 21 and 23, and a second insulating layer 24 disposed outside the second coil 23. The second coil 23 is a primary coil and the first coil 21 is a secondary coil. Note that the installation of the second insulating layer 24 is optional. In the embodiment, the core 20 is a single slot wound core. The first coil 21 wound on the core 20 is sequentially formed by a first right-triangle area A1, a plurality of ramp areas A2, and a second right-triangle area A3.

Referring to FIG. 3, the first right-triangle area A1 formed by a set of layers providing a slanted surface a100 and an external layer L5 is wound by the following steps. First, a first layer L1 of the set of layers is a front layer wound in parallel along a first direction D1 along the first end 201 to the second end 202 of the core 20. Then, a second layer L2, a next layer subsequent to the first layer L1, is wound and bent at a beginning wound position (i.e. the position of the circle No. 6) selected from a region near an end wound position (i.e. the position of the circle No. 5) of the first layer L1 (previous layer), above the circle No. 4, along a second direction D2 opposite to the first direction D1 of the first layer L1 toward the first end 201 of the core 20. The rest layers of the set of layers, i.e., a third layer 3 and a fourth layer L4, and the slanted surface a100 are outwardly formed by repeating the winding sequence of the first and second layers L1 and L2.

Then, the first coil 21 in the ramp areas A2 are wound back and forth along the slanted surface a100 of the first right-triangle area A1. A residual region is formed between the ramp areas A2 and the core 20. Thus, the first coil 21 in the second right-triangle area A3 is inwardly wound opposite to the winding sequence of the first right-triangle area A1 to form the residual region.

Therefore, a first coil 21 is wound around the core 20 by forward winding the first coil 21 from the first end 201 of the core 20 toward the second end 202 of the core 20 as the first layer L1, backward winding the first coil 21 above the first layer L1 toward the first end 201 of the core 20 from a position near a stop point of the first layer L1 and repeatedly performing the forward and backward winding to form a first right-triangle area A1. Then, the winding of the first coil 21 along the slanted surface of the first right-triangle area A1 starts from repeatedly forward winding toward the second end 202 of the core 20 and then backward winding toward the first end 201 of the core 20. Then, the first coil 21 is wound by a winding way opposite to that of the first right-triangle area A1.

As shown in FIG. 3, the first coil 21 is predetermined to be formed with five layers L1-L5. The first right-triangle area A1 is formed from a 1^(st) circle (No. 1) to 15^(th) circle (No. 15). The ramp areas A2 are formed from a 16^(th) circle (No. 16) to 70^(th) circle (No. 70). The second right-triangle area A3 is formed from a 71^(st) circle (No. 71) to 85^(th) circle (No. 85). The first layer L1 of the first right-triangle area A1 is wound by five circles, including the 1^(st) circle (No. 1) to the 5^(th) circle (No. 5) in parallel. The second layer L2 of the first right-triangle area A1 is wound by four circles, including the 6^(th) circle (No. 6) to the 9^(th) circle (No. 9) in parallel and toward the first end 201 of the core 20, wherein the 6^(th) circle (No. 6) is located on the 4^(th) circle (No. 4). The third layer L3 of the first right-triangle area A1 is wound by three circles, including the 10^(th) circle (No. 10) to the 12^(th) circle (No. 12) in parallel and toward the second end 202 of the core 20, wherein the 10^(th) circle (No. 10) is located on the 9^(th) circle (No. 9). The fourth layer L4 of the first right-triangle area A1 is wound by two circles, including the 13^(th) circle (No. 13) to the 14^(th) circle (No. 14) in parallel and toward the first end 201 of the core 20, wherein the 13^(th) circle (No. 13) is located on the 11^(th) circle (No. 11). The fifth layer L5 of the first right-triangle area A1 is wound by one circle, i.e., the 15^(th) circle (No. 15) in parallel and located on the 14^(th) circle (No. 14). Thus, the first right-triangle area A1 is formed.

In the embodiment, the ramp areas A2 include eleven ramp areas, from a 1^(st) ramp area R1 to 11^(th) ramp area R11. For example, the first ramp area R1 is formed from the 16^(th) circle (No. 16) to the 20^(th) circle (No. 20), and the second ramp area R2 is formed from the 21^(st) circle (No. 21) to the 25^(th) circle (No. 25). The position of the circle No. 20 is defined as an end wound position of the first ramp area R1, and the position of the circle No. 21 selected near the end wound position (the position of the circle No. 20 of the first ramp area R1) is defined as a beginning wound position of the second ramp area R2. The winding direction of the second ramp area R2 is opposite to that of the first ramp area R1. Thus, the first ramp area R1 to the 11^(th) ramp area R11 along the slanted surface a100 of the first right-triangle area A1 is formed inward to outward, thus forming the ramp areas A2.

The second right-triangle area A3 formed from a 71^(st) circle (No. 71) to 85^(th) circle (No. 85) is an inverse right-triangle area or a residual region formed between the ramp areas A2 and the second end 202 of the core 20. Thus, using a winding method opposite to that of the first right-triangle area A1, the second right-triangle area A3 is formed.

Compared to the conventional core divided by the blocking walls into eleven slots for forming the winding with fifty-five circles, the ramp areas A2 of the embodiment, wound next to the 5^(th) circle (No. 5), turned back and forth for eleven times, results in the same effect as the conventional core. Additionally, the first right-triangle area A1 and the second right-triangle area A3 are equilibrium to two slots. Thus, the voltage converting rate of the embodiment is superior to the conventional slotted transformer, and at least 30 percent of volume can be reduced.

According to the above-described features of the embodiment, the circle number of each of the circles is surrounded by circles with adjacent circle numbers. Therefore, the power jump can be prevented. Moreover, the blocking walls noted in the conventional transformer can be omitted. Further, the first and second right-triangle areas of the transformer of the embodiment provide a higher efficiency than the conventional one. Thus, costs and volume of the transformer can be reduced.

While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. 

1. A transformer comprising: a core comprising a first end and a second end; and a first coil wound around the core by forward winding the first coil from the first end of the core toward the second end of the core as a first layer, backward winding the first coil above the first layer toward the first end of the core from a position near a stop point of the first layer and repeatedly performing the forward and backward winding to form a first right-triangle area; winding the first coil along a slanted surface of the first right-triangle; and winding the first coil by a winding way opposite to that of the first right-triangle area.
 2. The transformer as claimed in claim 1, wherein the winding of the first coil along the slanted surface of the first right-triangle area starts from repeatedly forward winding toward the second end of the core and then backward winding toward the first end of the core.
 3. The transformer as claimed in claim 1, further comprising a second coil wound outside the first coil.
 4. The transformer as claimed in claim 3, wherein the second coil is a primary coil, and the first coil is a secondary coil.
 5. The transformer as claimed in claim 3, further comprising a first insulating layer disposed between the first and second coils.
 6. The transformer as claimed in claim 5, further comprising a second insulating layer disposed outside the second coil.
 7. The transformer as claimed in claim 1, wherein the core comprises a single slot.
 8. A coil winding method for forming a coil on a core with a first end and a second end, comprising the steps of: forward winding the first coil from the first end of the core toward the second end of the core as a first layer, backward winding the first coil above the first layer toward the first end of the core from a position near a stop point of the first layer and repeatedly performing the forward and backward winding to form a first right-triangle area; winding the first coil along a slanted surface of the first right-triangle; and winding the first coil by a winding way opposite to that of the first right-triangle area.
 9. The coil winding method as claimed in claim 8, wherein the winding of the first coil along the slanted surface of the first right-triangle area starts from repeatedly forward winding toward the second end of the core and then backward winding toward the first end of the core.
 10. The coil winding method as claimed in claim 8, further comprising winding a second coil outside the first winding.
 11. The coil winding method as claimed in claim 10, wherein the second coil is a primary coil, and the first coil is a secondary coil.
 12. The coil winding method as claimed in claim 10, further comprising forming a first insulating layer between the first and second coils.
 13. The coil winding method as claimed in claim 12, further comprising forming a second insulating layer outside the second coil.
 14. The coil winding method as claimed in claim 8, wherein the core comprises a single slot. 